CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Net revenue	$ 112,685	$ 0	$ 112,685	$ 0
Costs and expenses:
Cost of revenue	110,931	0	307,951	0
Research and development	6,094,921	3,190,178	10,482,000	5,995,124
Selling, general and administrative	5,377,784	3,904,403	10,489,479	7,120,615
Total costs and expenses	11,583,636	7,094,581	21,279,430	13,115,739
Loss from operations	(11,470,951)	(7,094,581)	(21,166,745)	(13,115,739)
Interest income, net	107,818	16,183	211,151	19,760
Net loss	(11,363,133)	(7,078,398)	(20,955,594)	(13,095,979)
Net loss attributable to common stockholders	$ (11,363,133)	$ (7,078,398)	$ (20,955,594)	$ (13,095,979)
Net loss per share attributable to common stockholders - basic and diluted (in usd per share)	$ (0.71)	$ (0.47)	$ (1.31)	$ (1.04)
Weighted-average number of common shares outstanding — basic and diluted (in shares)	16,105,555	15,034,764	15,974,544	12,620,771